Spinning bucket and method of making it



0. w. ANDERSON srnmm; BUCKET mo us'mon or wane rr Oct. 10, 1950 Filed July 26, 1947 Patented Oct. 10, 1950 srmumc nucxa'r nun mrrnon or MAKING rr Oscar W; Anderson, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Par, a corporation of Pennsyl Application July 26,119"; Serial No. 763,867

screams. (cast-1s) This invention relates to spinning buckets and the method of making them.

Spinning buckets of impregnated fibrous ma-' terial are extensively-employed in the manufacture of rayon. As the buckets are operated at a high rate of speed, it has been necessary to reinforce the buckets to enable them to withstandthe centrifugal force developed during use. Steel wires or bands have been generally incorporated in the internal structure of the wall member of the bucket as the reinforcing medium, suchbands or wires being disposed circumferentially within the confines of the wall of the bucket.

In using steel wire as the reinforcing agent, considerable difficulty is sometimes encountered in effecting a bond between the resinous binder of the bucket and the steel. Where an initial bond-is efl'ected, it is found that such bond is sometimes destroyed in use because of the dinerence in the coeflicient of expansion between the steel and the completely reacted resin. Further.

as the steel reinforcement is sometimes attacked by the acids encountered in the spinning of rayon,

the steel bands must necessarily, be embedded within the confines of the wall member requiring additional handling of the components of the bucket during the process of makingthe spinmolding process. A modified form of cloth which utilizes a combination of glass fiber warp threads and cotton woof threads has been used to a small extent,- but ,the additional cost of producing the special glass-fiber cotton yarn fabric detracts from its general use.

An object of this invention is to provide a new and improved spinning bucket having fiber glass cloth in the wall member thereof as a reinforcing medium.

Another object of this invention is to utilize a plurality of turns of fiber glass cloth as the reinforcing medium in the side walls of the spinning bucket and to so cushion such glass cloth during the molding process that the glass cloth will not rupture.

A further object of this invention is the prober which incorporates fiber glass cloth having a cord fabric weave therein as the" reinforcing member.

A more specific object of this invention is to provide a molded spinning bucket having a wall member in which alternate turns of impregnated cellulosic material and of impregnated fiber-glass cloth are employed internally of the wall member, the cellulosic material fuctl'oning to cushion the glass cloth to prevent rupture thereof during the molding of the bucket.

1 Another object of this invention is to provide a method of making spinning buckets of impregnated fibrous material in which fiber glass is introduced as a reinforcing medium in such a manher as to be cushioned against stresses encountered during molding.

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawing, in which: v

Figure 1. is a view in section of a spinning bucket embodying this invention;

Fig. 2 is a schematic representation, greatly out of proportion, of the formation of a cylinder employed in forming a wall member of the spinning bucket of Fig. 1;

Fig. 3 is a vertical section through a mold illustrating the moldingof the spinning bucket shown in Fig. 1; and r Fig. 4 is a view in section greatly enlarged of a section of the cylinder or side wall of the spinning bucket embodying the teachings of this invention. I

Referring to Fig. 1 of the drawing, there is illustrated a spinning bucket it having a base member l2 and a wall member l4 extending outwardly from the base member. The base member l2 and the wall member I are formed of' fibrous material impregnated with a heat convertible resinous binder such as phenol formaldehyde, urea formaldehyde, or the like. The base member I2 is preferably formed of a quantity of comminuted or chopped fabric impregnated with a resinous binder and one or more facing sheets it of cloth disposed over the upper end of the base member so that when molded the bottom of the internal cavity of the spinning bucket It will have a finished appearance. As opposed to the chopped or macerated material forming the base member t2, the wall member I4 is pref- .erably formed of a plurality of turns or layers of fibrous material impregnated with resinous binder. the lower end of the wall member it vision of a spinning bucket having awall meme to merging with and being bonded to the comcut into predetermined lengths to give a required I height to the wall member I4 when molded integrally with the base member I2. As illustrated in Fig. 2 of the drawing,the cylinder i8 is formed of composite material in that turns 26 of cellulosic material impregnated with the resinous binder and turns 28 of fiber glass cloth 22 preferably of a cord fabric weave which is also impregnated with the resinous binder are wound in a predetermined manner from supply rolls 2| and 23, respectively, onto, a mandrel 24 to a required thickness to give a wall member l4 of predetermined thickness when molded.

In formlng the cylinder l8, a number of turns 26 of the impregnated cellulosic material, such as cotton cloth, are wound directly upon the mandrel 24 and when a predetermined number of the turns 26 are formed thereon, the impregnated glass cloth 22 is interleaved with the impregnated cellulosic material to form a plurality of continuous turns 28 alternately with the turns 26 of the impregnated cellulosi'c material. In positioning the glass cloth 22 in the assembly, it is preferred to So introduce the cloth22 that the warp threads thereof are disposed circumferentially about the cylinder to impart strength thereto and to the wall member of the molded bucket.

A glass cloth particularly useful in the cylinders is one having a cord fabric weave with a construction of 49 warp threads and 30 filler threads per inch and about .009 inch thick with a weight of 8.9 ounces per square yard. The alternate layers 26 and 28 of impregnated cotton cloth and impregnated glass cloth, respective1y, are thus formed until a predetermined number, usually 6 or 7, of the turns 28 of glass cloth are embodied in interleaved relation with the turns 26 of cotton cloth, after which only turns 26 of the cotton cloth are added to the composite structure forming the cylinder I8. Thus the cylinder 18 is formed of only a predetermined number of turns of the impregnated cotton cloth at the inner and outer surfaces of the cylinder 18 and of alternate layers or'turns of the impregnated cotton cloth and fiber glass cloth disposed internally of the cylinder.

Where it is desired to have a thicker rim member at the upper edge of the spinning bucket 10, as illustrated in Fig. 1. a band 30 of impregnated cotton cloth is positioned about the end of the cylinder 18, as illustrated in Fig. 3, to cooperate with the cylinder 18 in forming the rim. With the cylinder l8 formed in the manner described and severed into predetermined lengths depending cavities 40, is positioned over the upper end of the cylinder l8. As shown, the female mold member 3-8 has a cavity therein for cooperating with the male mold member 32 for imparting the required shape to the molded splnningbucket N. The mold members 32 and 38 have cooperating side wall surfaces which are slightly tapered for giving a slope to the molded wall member l4.

Where desired, the cylinder l8 and the preform 34 can be preheated to soften the resinous binder before positioning them with respect to the mold member 32. After the components are assembled as illustrated in Fig. 3, the female mold member 38 is actuated downwardly or the male vmember 32 is actuated upwardly to heat and compact the cylinder I8 and the preform 34 to form the spinning bucket I0 illustrated in Fig. 1. The

3 heat and pressure may vary somewhat depending on the resinous binder employed, but should be sufilcient to effectively cure the resin and con-- solidate. the co'mponentsninto an integral body. In practice, a pressure of about 3000 pounds per squazre inch and heat at a temperature of 180 C. to 185 C. for a period of time of 45 to 50 minutes is satisfactory for molding the buckets. During the molding operation, the end of the cylinder i8 adjacent the base member I2 is turned inwardly as illustrated in Fig. 1 and merges with and is bonded to the comminuted material forming the base member l2.

During the molding operation as described "hereinbefore, the cylinder I8 is forced over the tapered mold member 32, with the result that stresses are set up in the turns of the cylinder l8 since the tapered mold member 32 has a larger outer diameter than the inner diameter of the cylinder l8. However, bywin'dingthe cylinder la in the manner described hereinbefore, with alternate turns 26 of cotton cloth and turns 28 of fiber lass of the cord fabric weave as better illustrated in Fig. 4, it is found that the layer 26 of cotton cloth disposed betweenadjacent layers 28 of the glass cloth is resilient and so cushions the glass cloth as to offset any stresses induced therein during the molding operation and thereby prevents rupture of the glass cloth. Thusin the Ainal product illustrated in Fig. 1, the wall memupon the required height of the wall member I4,

the base member l2.

With the clyinder l8 and the preform 34 disposed on the male mold member 32 as illustrated,

a heating medium, for example, steam is supplied to the cavities 33 of the mold'member 32 and a female mold irerrber 38 which is also heated by means of steam or the like being supplied to the In practice, since the glass cloth of the composite structure has a higher elastic modulus than the cotton cloth, it is found that the centrifugal stresses are taken up by the warp threads of the turns 28 of fiber glass in such a fashion that there is a more homogeneous distribution of stresses throughout the structure and that the resulting structure has sufficient strength to withstand the forces encountered in service.

Spinning buckets formed in accordance with this invention and loaded as in actual practice have been operated at speeds of up to 17,400 R. P. M. without failure of the bucket structure.

By forming the spinning bucket in the manner described hereinbefore, previous modes of forming spinnlng'buckets have been greatly simplified resulting in savings in production costs and eliminating numerous preforming operations and inspections. Further, in eliminating the various operations required heretofore, the amount of scrap has been greatly reduced with resultant v economies in the manufacturing cost of the spinning bucket.

A distant advantage of the spinning bucket produced in accordance with this invention as opposed to the prior art steel wire reinforced buckets is the elimination of residual stresses introduced by reason of the difference in thermal coeflicient of contraction of the steel wire reinforcement with respect to the impregnated fibrous material.

The spinning buckets of this invention are formed of standard materials and can be readily reproduced while the method can be readily duplicated. The strength of the resulting bucket is sufllcient for all service requirements. Further, since the reinforcing member is of fibrous material and is utilized as part of the wall member, the weight of the spinning bucket is reduced with respect to the prior'art reinforced spinning buckets.

I claim as my invention;

1. A spinning bucket comprising a base and a wall member extending from the base, the wall member comprising a plurality of internal and external layers of cloth impregnated with a resinous binder, the external layers of the wall member being fibrous cellulosic material andthe internal layers being alternate layers of cloth of fibrous cellulosic material and of cloth or fiber glass having a cord fabric weave.

2. A spinning bucket comprising a base member and a wall member extending from the base, the wall member comprising a plurality of internal and external layers of cloth impregnated with a resinous binder, the external layers of the wall member being of cotton cloth and the internal layers being alternately cotton cloth and fiberglass cloth having a cord fabric weave.

3. A spinning bucket comprising a base member and a wall member extending from the base, the wallmember comprising continuous turns of cotton cloth and turns of fiber-glass cloth having a cord fabric weave interleaved between certain of the internal turns of cotton cloth only to give alternate layers of cotton cloth and fiber glass cloth internally only of the wall member and outer layers of cotton cloth, the cloth of the wall member being impregnated with a resinous binder.

4. A spinning bucket comprising a base mem- 5 ber and a wall .member extending from the base, the wall member comprising a pluralityoi. layers of cotton cloth and fiber glass cloth having a cord fabric weave impregnated with a resinous binder consolidated into an integral unit with the base member, the layers of the impregnated fiberglass cloth in the wall member being fewer in number than the layers of impregnated cottoncloth and being interleaved between predetermined internal layers of the impregnated cotton cloth only to provide alternate layers of cotton cloth and fiber-glass cloth internally only of the wall member and outer layers of cotton cloth.

. 5. In the method of making spinning buckets, the steps comprising, winding a plurality of turns of impregnated cotton cloth to form a cylinder having a predetermined diameter, continuing the winding of additional turns of the cotton cloth while interleaving a turn of impregnated fiber-glass cloth between adjacent turns of the cotton cloth to introduce a predetermined number of alternate layers of cotton cloth and fiberglass cloth in the cylinder to provide a resilient layer between adjacent layers of the fiber-glass cloth, thereafter winding additional layers of the impregnated cotton cloth to complete the cylinder, and molding the cylinder and other moldable material to produce a spinning bucket having a wall member formed of the cylinder, the resilient layer of cotton cloth cushioning the adjacent layers of fiber-glass cloth as they are stressed during the molding operation to. prevent rupture of the turns of the fiber-glass cloth.

6. -A spinning bucket comprising a base and a wall member extending from the base, the wall member comprising a plurality of internal and external layers of cloth impregnated with a resinous binder, the external layers of the wall member being fibrous cellulosic material and the. internal' layers being alternate layers of cloth of fibrous cellulosic material and of cloth of fiber glass having a cord fabric weave and having the warp threads thereof disposed circumferentially about the wall member.

OSCAR W. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

'UNI'I'ED STATES PATENTS Lincoln Aug; 27, 1946 

